A so-called reverse-flow combustion chamber is generally made up of metal sheet stamped to constitute shells. The shells are assembled together. For assembly purposes, the shells often have annular tongues that are assembled flat thereto by seam welding.
These welded-on tongues project outside the combustion chamber, thereby leading to head losses in the stream of air flowing around the combustion chamber. In addition, mechanical weakness remains in these tongues, particularly in a reverse-flow combustion chamber, while the outer bend of the chamber is being subjected to bending.
In addition, that assembly technique leads to thermomechanical stresses and raises problems of accessibility if it is desired to use a laser to perforate the combustion chamber.
Attempts have recently been made to reduce the number of annular tongues by making use of butt welded assembly techniques. Nevertheless, the solutions that have been envisaged until now have not made it possible completely to eliminate seam welding.